Aluminum cleaning compositions



UnitedStatcs atet 3,255,118 ALUMINUM CLEANING COMPOSITIONS James W. Carroll, Lafayette Hill, and Harold V. Smith,

Philadelphia, Pa., assignors to Pennsalt Chemicals Corporation, Philadelphia, Pin, a corporation of Pennsylvama N Drawing. Filed Dec. 29, 1961, Ser. No. 163,064

6 Claims. (Cl. 252-137) This invention is directed to new cleaning compositions for use on aluminum or aluminum alloys comprising an alkali metal polyphosphate, an alkali metal tetraborate and hexavalent chromium in the form of a water soluble salt in specific proportions.

Our invention also embodies aluminum cleaning compositions comprising an alkali metal polyphosphate, an alkali metal tetraborate, hexavalent chromium as indicated above and one-half to five parts by weight of at least one organic detergent selected for its ability to remove soils encountered in the processing of aluminum metal or to prevent the redeposition of such soil. The organic detergents having a special utility in the cleaning of aluminum or its alloys are condensed naphthalene sodium sulfonate, alkyl aryl sulfonic acids, and their alkali metal salts and alkyl phenol-ethylene oxide condensate.

In one form of our invention the cleaner composition comprises an alkali metal polyphosphate, an alkali metal tetraborate, hexavalent chromium in the form of a water soluble salt in specific proportions, together with an aluminum sequestrant.

The most efiicient aluminum cleaners of our invention comprises an alkali metal polyphoshate, an alkali metal tetraborate, hexav-alent chromium, at least one of the position in aqueous solution to effect cleaning of aluminum and aluminum alloys.

Industrial metal cleaners are usually based upon strong alkalis such as caustic soda, sodium orthosilicate or trisodium phosphate compounded with detergents and/or sequestering agents. In the cleaning of aluminum such products cannot be used because the strong alkaline materials will seriously corrode or etch the aluminum. For this reason aluminum cleaners in the past have usually been com-pounded with silicates which are milder alkalis and which also provide a silicate film which inhibits the corrosion of aluminum by any strong alkali which might be present. Sodium metasilicate, for example, is a good detergent which is widely used in aluminum cleaners.

Many aluminum cleaning operations precede a subsequent etching, anodizing or chemical brightening operation. In such treatments, there is a serious disadvantage in using sodium metasilicate in the prior cleaning operation. The silicate forms a protective film on the aluminum which remains and interferes with uniform etching, anodizing or chemical brightening of the metal.

To overcome this disadvantage it is usually necessary to dip the metal which has been cleaned in a cleaner con- ;taining a silicate in an acid before proceeding with the processing of the metal. An example of aluminum cleaner containing a silicate followed by an acid treatment is Patented June 7, 1966 that shown in US. Patent 2,709,847. The use of an acid dip in the processing of aluminum metal requires additional equipment, chemicals and material handling, which adds considerably to the cost of processing the metal.

Accordingly, it is one of the objects of this invention to formulate an alkaline cleaning composition for use on aluminum which will not etch the aluminum and which will not leave a film on the-aluminum which requires a chemical operation to remove before aluminum can undergo further chemical processing.

Many cleaners heretofore used in processing aluminum alloys have been based primarily on sodium hydroxide, sodium carbonate or sodium bicarbonate and it has been found that such cleaners are unstable in use, particularly in regard to pH and in the control of the pH. Since aluminum cleaners cannot be too alkaline, in order to prevent etching, the pH must be controlled within a fairly close range. When the above chemicals ars used to provide alkalinity and detergency, there is no inherent resistance to a lowering of pH when cleaning acid type soils, and hence the baths are of short life or become unstable.

We have now found that by the use of alkali metal polyphosphates and alkali metal tetraborates, in specific ratios, our cleaners have the desired pH range, and, in addition, have an inherent stability to resist changesin pH due to acid contaminants for a long period oftime.

It is also necessary in aluminum cleaners to provide an inhibitor against corrosion. The prior art has used various materials as inhibitors, such as arsenic and antimony salts, as disclosed in U.S. Patent 2,303,399. We have found that hexavalent chromium is a desirable inhibitor for our aluminum cleaning compositions. As mentioned before, the use of silicates is undesirable because of the separate acid treating step to remove the silicate film. The use of antimony and arsenic salts is undesir-.

able because of the toxicological problem and cost.

There are quite often present on the aluminum alloys soils which are not easilyor completely removed by the detergency provided by alkaline compounds. To remove them some aluminum cleaners have incorporated.

solvents such as tertiary butyl alcohol as disclosed in U.S.. 2,762,732. Mineral spirits, such as heavy naphtha,

have also been used for this purpose. vIn some cases the prior art has used a separate solvent cleaning operation to remove specific soils from the aluminum. In US Patent 2,705,500 the patentee discloses the use of trichloroethylene as a separate degreasing step prior to the use of an alkaline cleaning operation.

The most prevalent soils which contaminate the aluminum metal are cutting or stamping oils and bufilng comdepositing upon the metal as a grease or as a stain. It is not enough that the metal must be cleaned while it is in the cleaning solution; it must remain clean until it has passed through the subsequent rinsing stage. If the aluminum is soiled or stained, it would be unsuitable for architectural applications such as for window frames or doors. Another problem in formulating a metal cleaning composition is to select the materials which will operate satisfactorily in the great varieties of water encountered in different sections of the country. Thus, the choice of a detergent system which will remove all kinds of soils encoutered in aluminum processing such as cutting oils and buffing compounds, and which will prevent redeposition of the soils and staining is a diflicult problem.

We have now discovered a new cleaning composition for aluminum and aluminum alloys which will clean aluminum contaminated with all kinds of soils without etching the aluminum and which permits the aluminum metal to undergo further chemical processing with nothing further required other than a water rinse. In addition to the above advantages, our composition has been carefully formulated so that it will not undergo caking during storage and shipping and will remain free flowing and readily available for use after long storage periods.

The principal component of our aluminum cleaning composition is alkali metal tetraborate, preferably the sodium or potassium salts because of their availability. The alkali metal tetraborate must be present at least at 35 parts by weight of the solid composition, otherwise there is poor cleaning and soil removal. A principal advantage of the tetraborate is that its provides good detergency at the desired pH of 8 to 10 and in addition, it has inherent buffering ability. The alkali metal tetraborate concentration can be as high as 92 parts by weight, while the preferred concentration is about 70 parts by weight.

The other alkaline detergent which we require in our composition is one or more members of the group known as the alkali metal polyphosphates. The alkali metal polyphosphates are molecularly dehydrated alkali metal phosphates distinguishable from the orthophosphates in that their alkali metal oxide (M to phosphorus pentoxide (P 0 ratio is substantially less than three to one, the ratio in the orthophosphate (M PO The polyphosphates that are applicable to our aluminum cleaning composition have an M 0 to P 0 ratio of two to one or less. Examples of suitable alkali metal polyphosphates include tetrasodium pyrophosphate (ZNa O' P205 01' Na4P O7) sodium tripolyphosphate (5Na O-3P O or Na P O sodium hexametaphosphate [(Na O-P O or Na P O and the equivalent water soluble potassium salts. As used throughout the specification and claims, the term alkali metal'polyphosphate shall have the meaning herein given. The preferred alkali metal polyphosphate for use in our cleaning compositions is the tetrasodium pyrophosphate.

The alkali metal polyphosphates must be present in at least 5 parts by weight of the dry composition and may be present as high as about 35 parts of the dry composition. The preferred proportion is 17 parts by weight of the dry mixture.

The combination of alkali metal tetraborates and alkali metal polyphosphates within the above concentration ranges is the only combination of alkaline cleaning agents which we have discovered which will satisfactorily remove soil from aluminumand its alloys and which also has a pH in aqueous solution within the range of 8 to 10, a range that will not seriously corrode or etch the aluminum or leave undesirable deposits on the aluminum being cleaned.

We have found that the hexavalent chromium is the only corrosion inhibitor which is compatable with the particular alkali and detergent system which we have formulated which will not leave a permanent film or stain on the aluminum metal being processed, and in this respect, the hexavalent chromium has a particular advantage over silicates which have heretofore been used for corrosion inhibition of aluminum in cleaning compositions. Even though hexavalent chromium may impart some slight chromium color to the solution, this is readily rinsed by water so that there is no permanent film or color remaining on the metal. The choice of the particular detergents in our cleaning composition assures that the chromium readily rinses off along with the other soil.

We have discovered that at a pH of 10 in aqueous solution there must be present at least 0.5 gram per liter of hexavalent chromium in order to prevent corrosion of the aluminum. At lower pH the amount of hexavalent chromium required to prevent corrosion is not as great. At a pH of 8.5 there is no attack on the aluminum with only 0.05 gram per. liter of hexavalent chromium. The hexavalent chromium must be present in the cleaning composition within the range of 0.3 to 4 parts by weight, and is preferably present at 1.8 parts by weight.

The hexavalent chromium may be supplied in the form of chromic acid, alkali metal chromates, alkali metal dichromates or most any source of water soluble hexavalent chromium. Where the term hexavalent chromium is used throughout the specification and claims, we mean hexavalent chromium as supplied in the form of a water soluble dichromate, chromate or chromic acid or anhydride. If 5 parts by Weight of hexavalent chromium are specified in a composition, this could be supplied, for example, by 14.1 parts of potassium dichromate or 18.6 parts of potassium chromate. 1

While the above cleaning composition containing to 92 parts of alkali metal tetraborate, 5 to 35 parts of alkali metal polyphosphate and 0.3 to 4 parts of hexavalent chromium is an effective detergent composition for aluminum in aqueous solution, it Will not completely remove all types of soil, especially bufiing compounds. Additional cleaning power may be supplied by one or more specific detergents.

We have found that the alkyl aryl sulfonic acids and their alkali metal or ammonium salts are effective detergents in the above cleaning composition. The alkyl aryl sulfonic acids and salts must be present within the range of from 0.5 to 5 parts by weight and are preferably present at 2 parts by Weight. The preferred alkyl aryl sulfonate is dodecyl benzene sulfonic acid and its sodium salts, although other aryl sulfonic acids having a C to C alkyl substituent are useful in our cleaning composition. The useful aryl components are benzene and naph thalene. The preferred salts of the alkyl aryl sulfonic acids are the alkali metal and ammonium salts, although other water soluble salts can be used.

Another group of detergents which we have found useful in our cleaning composition are the alkylphenolethylene oxide condensation products having the formula wherein R is an alkyl group having from 6 to 12 carbon I atoms, and Where n has a value of from 8 to 12. Preferred alkyl substituents are the octyl and nonyl radicals.

Either the alkyl aryl sulfonate or the alkylphenolethylene oxide condensation product is effective in the removal of soils such as rolling oils, stamping and forming lubricants, and bufling compounds. may be used by itself, or, more effectively, both detergents may be used in the cleaner composition. At least 0.5 part by weight of the alkylphenol-ethylene oxide condensation product must be present in the dry granular composition and as much as parts will beuseful. Any larger concentrations will not provide additional cleaning.

In addition to having the above detergents which are effective in removing various types of soil from the aluminum metal and aluminum alloys, it is desirable and in. some cases necessary to have organic detergents present which will prevent redeposition of soil and/or the staining of the aluminum after the soil has been removed. Thus, We have found that the condensed naphthalene sodium sulfonates are particularly effective in preventing the redeposition of soil and in preventing the staining of aluminum. This product will be referred to throughout the specification and claims as condensed naphthalene sodium sulfonate. More specifically, it is the sodium salt of the condensation product of naphthalene sulfonic acid and formaldehyde. This product may be prepared in the manner set forth in US. Patent No. 1,336,759. The condensed naphthalene sodium sulfonate may be conveniently purchased under the trade name Tamol N, a product of the Rohm & Haas Company. The condensed naphthalene sodium sulfonate may be used in conjunction with one or more of the above detergents or it may be used without the above detergents. It is most effective, however, when used with one or more of the organic detergents.

It is also desirable that our aluminum cleaning composition have in it a sequestrant to prevent the redeposition of aluminum salts.

Even though our cleaning compositions are formulated to operate at a pH which will not seriously corrode or etch the aluminum and are buffered for long lasting service, some etching of the aluminum will take place. Thus, it is necessary that an aluminum sequestrant be present in the composition. The sequestrant may be .used alone with the alkali metal polyphosphate, alkali metal tetraborane and hexavalent chromium, but preferably, it is used with one or all of the organic detergents.

The most useful aluminum sequestrant is sodium gluconate and this must be present in the dry granular composition at a concentration of at least 0.5 part by weight and it may be as high as 5 parts by weight. Preferably the concentration is 1 part by Weight. Gluconic acid and the alkali metal salts are also suitable aluminum sequestrants. The glucom'c acid and the alkali metal salts thereof are polyhydroxy carboxylic acids and may be characterized by the formula CH OI-I(CHOH) COOH, wherein n is 4 for gluconic acid. In other polyhydroxy carboxylic acids which are useful aluminum sequestrants, the n in the above formula may vary from 2 to 6. Suitable hydroxy monobasic acids are sacharric, heptogluconic and gluconic.

. -0.5 to 5 parts by weight, and preferably will be at 1 part by weight. The aluminum sequestrants prevent the for- Either detergent 6 mation of aluminum salts from depositing on the cleaned aluminum.

Our aluminum cleaning compositions are dissolved in water at concentrations of from 2 to 10 ounces per gallon. Preferably the composition is used at 4 to 5 ounces per gallon, and higher concentrations may be used, depending on the difiiculty of removing the particular soil encountered. However, concentrations much in excess of 10 ounces per gallon may not dissolve all of the ingredients and hence are not practical.

The temperature at which the aluminum and aluminum alloys are subjected to in our cleaning bath are from room temperature to about F. Temperatures higher than 180 F. should not be used as there is a tendency for etching of the aluminum to take place at these temperatures. Moreover, higher temperatures accelerate the reversion of the polyphosphates to the orthophosphates. Agitation in the cleaning bath is desirable but not necessary. Agitation can be supplied mechanically or by the use of air.

As mentioned earlier, the selection of alkalis and their ratios was made to obtain a composition which, in aqueous solution, at the useful concentrations, would give a pH within the range of 8 to 10. Preferably, the pH is about 9.2 or 9.3. Within this pH range there is only a little tendency for the alkali to corrode the aluminum.

The cleaning time will vary from 30 seconds to 15 minutes depending on the difiiculty of removing the soil. Stamping or cutting oils are readily removed, particularly from 2S aluminum, and normally an immersion time of 30 seconds is all that is required to remove this type of soil. When one is attempting to remove bufiing compounds or heavy grease and Wax coatings from aluminum, then an immersion time of 15 minutes may be required.

It is a particular advantage of our compositions, that the aluminum metal or alloys may proceed to a subsequent chemical treating operation with only an intermediate rinsing operation. A single cold water rinse is all that is required before the metals may proceed to anodizing or brightening operations.

The best mode of using our novel cleaning composiparts were observed for completeness of soil removal and for corrosion of the aluminum.

Table I Soil on Aluminum Sheet Sodium Tet-raborate, Parts Mineral Oil Butling Compound Metal by weight Etching 0i Cleaner Removal Rinsing Removal Rinsing (in min.) (in min.)

15 Good 20 N 0 attack. 15 do 20 Do. 10 do 25 Do. 35 10 d0 25 Trace attack 30..-; 9 do 20 Fair Slight attack. 25 7 do 10 P0011-.. Mild attack.

the dry granular cleaning composition. The remaining components were present as given in Table I. Tetrapotassium pyrophosphate can be substituted for the sodium salt in the above table with equal efi'iciency.

Tetrasodium pyrophosphate was compared for cleaning ability with sodium tripolyphosphate and sodium hexarnetaphosphate at concentrations in Water of 6 ounces per gallon and at 170 F. The alkalis were tested for cleaning ability against mineral oil and bufling compounds. The rinsing ability in cold water and the corrosion or staining of the aluminum by the cleaning operation was also observed. These tests are summarized in Table III.

Table III Effectiveness of Polyphosphate Cleaners Cleaner Composition Cleaning Ability Parts by weight Attack/Staining Rinsing (in on bufied 6063 cold water) aluminum Mineral Oil Bufling Compound (Kendall 50G) 70.0 sodium tetraborate, 17.0 No staining, no Complete removal Complete removal Good.

tetrasodium pyrophosihate. attack. in min. in min. 70.0 sodium tetraborate, 17.0 No attack, no .do Complete removal Do.

sodium tripolyphosphate. staining. in 22 min. 70.0 sodium tetraborate, 17.0 No staining, no Complete removal Cmoplete removal Very good.

sodium hexametaphosphate. attack. in 16 min. in 20 min.

used at a concentration of 6 ounces per gallon and the concentration of the alkali metal polyphosphate was successively lowered until either cleaning or rinsing was in adequate. The cleaning bath was operated at 170 F. The particular soils that were tested for removal were mineral oil, palm oil and buffing compound.

The remaining 13 parts by weight of the composition given in Table III are the same as in Tables I and II.

Various other combinations of alkaline detergents were formulated, as shown in Table IV, dissolved in water at 6 ounces per gallon, and then observed for their corrosion of aluminum metal, stability or other effects. In

As in Table I, the sum of the tetrasodium pyropho-sphate and sodium tetraborate was 87 parts by weight of corrosion.

general the formulations would not satisfactorily inhibit Sometimes where satisfactory corrosion inhibition was obtained, the components were incompatible, as noted by the precipitation in the solution. The pre- 39255 33 3352 3 PH ggggifg Stablhty cipitation left undesirable deposits on the cleaned metal.

Table I V 70.0 sodium tetraborate. Slight.

5 25.0 sodium nitrate. sass?- Cleaner Com osition, H Corrosion of Stability Parts by geight p aluminum 1.0 sodium gluconate.

70.0 sodium tetraborate. 9. 3 None. Clear solution. 60.0 sodium tetraborate. 9.0 Moderate. l7-ohtetrgsodmm 25.0 sodium bicarbonate.- 10 p 051) t hr 10.0 tetrasodium pyro- 5-otllotassmm phOSphate' 2 drama N c 2.0 Tergitol NPX. T INPX 2.0 DD BSA. 5 v sodmm gluconate' 1.0 sodium gluconate. 60.0 sodium tetraborate. 9. 05 Moderate. 201) q r blcflrbonfltea Tergitol NPX-an alkyl phenoiethylene oxide condensate having 15.0 disodium phosphate. the formula 3. ggesgitstiNPX.

. B 1.0 sodium gluconate. v R-O (CHzCHzO) n11 60.0 sodium tetraborate. 8.8 Moderate.

- where R is an alkyl group having from 6 to 12 carbon atoms and where 20.0 sod um bicarbonate. n has a value of from 8 to 12, manufactured by Carbide 6: Carbon sodmm mpolyphos Chemical Corporation. 2 gg fii' NPX b DDBSA90% solution of dodecylbenzenesullonic acid, manufacifi tured by Monsanto Chemical Co.

c Tamol N-c0ndensed naphthalene sodium sulfonate, manufactured 1.0 sodium gluconate. by Rohm & Haas Company. 9- sodium tetraborateht. Considerable The minimum amount of hexavaient chromium necesh zfs l i li i poly prempltatwn sary to inhibit the corrosion of an alkali metal tetrabor-ate- 15.0 Stadium bicarbonate. alkali :metal pyrophosphate cleaner system on aluminum 2:8 i fi g fifilffg imetal was determined by varying the pH of a cleaner E A- t composition used at a concentration of 4 ounces per galg mom lon of water and then observing the efiect of the solution 68-8 s g t tr t 5 Considerable on buffed aluminum immersed in the aqueous cleaner 3 b gfifif preclpl a system at 170 F. for 10 minutes. The pH of the solution 3-8 q q iggg was adjusted where necessary by the addition of sodium 1 hydroxide. Hexavalent chromium was added to the sodium gluconatecleaner system at the various levels indicated in Table V by the addition of computed amounts of potassium dichromate. The amount of corrosion was observed after a 10 minute immersion.

Table V C Hexavalent Chromium Content versus pH +u I Concentra- Attack on Aluminum at pH tion, gm./ liter Slight S1ight Trace..-"

In Table V the chromium was added to the following 60.0 sodium tetraborate. 9. 2 Very slight. Considerable composition: 30.0 mtonosodium phosprecipitation. Percent p a 5.0 sodium silicate. Sodium tetraborate 73.8 2:8 $35??? Tetrasodium pyrop-hosphate 17.9 1.0 sodium gluconate. 0 Sodium gluconate 1.05 0 sodium tetrabomte Considerab1e Condensed naphthalene sodium sulfonate (Tamol 35.0 monosodium phos- N) 2.10 Ja i- Alkyl phenol-ethylene oxide condensation product i-g E (Tergitol NPX) 3.16 so umguwmte' 5 Dodecyl benzenesulfonic acid 2.10 60.0 sodium tetraborate. 8. 4 Sh ht stainin Considerable 30.0 monosodium phoss vere corg precipitation, Various detergents and detergent combinations were 5 5 3553- fluosflicate ggi l gg added to a borargtetrasodium pyrophosphate cleaner sys- 210 TergitolNPX. interface, tern to determine the effect on removal of bufling com- -8 ggg fg pound from aluminum metal. See Table VI. The removal of the bufiing compound was observed by im- ;g-g$g %?g$g$3fi 3 12 gi i fg g mersing 6063 aluminum which had been buffed with phosphate. ing g as 11 bufiing compound. The immersion was at F. for 5-8 "A changed- 10 minutes with the cleaner concentration at 4 ounces 1:0 sodium gluconate. 7% per gallon of water and at a pH of 9.0. The percentage of detergent given is the percentage of a cleaner compoll sition composed of 60 parts of sodium tetraborate, 20 parts of tetrasodium pyrophosphate and 20 parts of sodium bicarbonate.

The remainder of the cleaner compositions used in the above tests was as follows:

Table VI I Percent Sodium tetraborate 70 Am a r 5 T t d h h t 17 m e raso mm pyrop osp a e o i ci fitltd Potassium dichromate Detergent System cleatner Nl-lspla- Tamol N 2 Remgvedl Tergitol NPX 3 Percent Dodecylbenzenesulfonic acid 2 Alkylhei;no%etl ylerx%d: condensation having thus described our invention we claim it as folpm 2 90 lows, in which all parts given are parts by weight: Alkylguhetnol ethylene oxide condensation VVB claim:

pm HEIMNPX 4 100 1. Acomposition for cleaning aluminum and its alloys Al y p ethylene Oxide o e a in a ueous solution c sisti s tial b i h 0 product, Tergitol NPX 2 90 a 1 S6119 1y y W: g I? Condensed naphthalene suliouate, Tamol an a a1 mvta tetra orate 3 to 2 P an a 31 N 1 metal polyphosphate5 to 35 parts, a water soluble podecylbemenesultonic acid 5 95 hexavalent chromium compound selected from the group Amylphenolethylene oxide condensation consisting of chromlc acid, alkali metal chromates and product, TergitolNIfIL 2 100 alkali metal d1chromates0.3 to 4 parts, and at least Dodecylbenzenesulfomc (191d 2 one organic detergent selected from the group consisting of Dodt'ceylbenzenesulionic acid 2 85 a sodium salt of a snlfonated condensation product of ???.fififltfliififtifffifif t 1 naphthalene and t e e m an alkyl aryl sulfonic acid and its alkali metal salts 1n Condensed naphthalene sulfonate, Tamol 5 85 which the alkyl group is C3 to C14, the aryl group I u is benzene and naphthalene, and Laury so ium su ate uponol WA n... 5 90 Alkylphenol ethylene' oxide condensation an alkyl phenol ethylene oxide condensate having the product, Tergitol NPX t 3 formula Alkylphenol ethylene oxide condensation 3O Dpgodufit, "iergitolfNPXnci 2 100 o ecy )enzenesu onic aci 3 Condensed naphthalene sulfonate, Tarnol R Q0 (0 H20 H20) H 1 Lauryl sodium sulfate, DuponolWA 1 50 h R 1k 1 h f 6 12 I w ere is an a y group aving rom to car- Laurylsodlm sulfateDuponolwA 5 bon atoms and where nhas a value of from 8 to Neutral sodium salt of tall oil acid, Dresi- 1 5 t 5 pa -t nate TX 5 1O 2 Th e composition of claim 1 together with 0.5 to 5 Neutral Sodmm Salt Dresiparts of an aluminum sequestrant selected from the group nate TX 20 75 consisting of Sodium salt of a sultated primary amine condensed with ethylene OX1 de, Triton a polyhydroxy carboxylic acid hav ng the formula QS-15 I 1 5o CH OH(CHOH) COOH where 12 1s 2 to 5 and its Sodium salt on sulfated pn-mary amine alkali metal salts, a polyhydric alcohol of the formula a e WWII e y 0X1 1e,Tr1t0n 5 60 CH OH(CHOH),,CH OH where 11 1S 2 to 5, and ethylenediamine tetraacetic acid and its alkali metal Alkanolamine condensate Emcol 5130 8.. 1 salts Alkanolamine condensate, nmcol naonfl- 5 3. A composition for cleaning aluminum and its alloys M f t db J T t C in aqueous solution consisting essentially by weight of an 5 2.1111 810 ure 1e er om any. b Manuuffactmeg gilgargidgz 12 g Chemical Com 50 alkali metal tetra borate-35 to 92 parts, an alkali met-a1 Man acture y o m aas ompany. t t v d Manufactured by L du Pont de Nemours & Cm polyphosphate 5 to 35 parts, a water soluble hexavalent :{WIIanuliacttureg1lgy geilculzs gowdgr Company. chromium compound selected from the group consisting 1' anu ac ure y o m aas ompany. z Manufactured by Emulsoa Chemical Corporation. ghromlc ggg metal (gh'OHliiEiS and alkzlilh The effectiveness of various sequestering agents was f iEg ZZZT fi i g f r fi gj 3 6 determined by observing the redeposition of soil and/ or so g g o p 3 f staining of aluminum 6063 immersed at 170 F. with vari- 50 um 5a t o mate ensanon Pro 0 cos cleaner compositions at 6 ounces per gallon of water naphthalene and q k concentration. Thesequestrant was used at 1% concenall alkyl aryl Sulfomc 'acld 111 whfch the alkyl group 15 tration and the soils involved were Kendall 50G mineral C t C and the aryl group 18 benzene and naphoil and Nu-Spra-Glu buffing compound. thalene, and their alkali metal salts, and

Table VII Cleaning Ability Sequestrant, percent by Attack/staining on bufied Binsmg weight 6063 aluminum in cold Mineral Oil Nu-Spra-Glu water (Kendall 50G) Buffing Compound Sodium gluconate, 1.0..-- No redeposition of soil. Complete removal Complete removal Good.

No staining. No in 15 min. in 20 min. attack. Sorbito], 1.0 do .....do .do Do. Ethylcnediamine tetradn do do Do,

acetic acid tetrasodium salt, 1.0.

Manufactured by .T. J. Sieler Company.

an alkyl phenol-ethylene oxide condensate having the formula R-QQ o memo) 11 where R is an alkyl group having from 6 to 12 carbon cu omcnom cn ou where n is 2 to 5, and ethylenediamine tetraacetic acid and its alkali metal salts.

4. A composition for cleaning aluminum and its alloys in aqueous solution consisting essentially by weight of sodium tetraborate35 to 92 par-ts, tetrasodium pyrophosphate5 to 35 parts, a water soluble hexavalent chromium compound selected from the group consisting of chromic acid, alkali metal chromates and alkali metal dichromates 0.3 to 4 parts, at least one organic detergent selected from the group consisting of a sodium salt of a sulfonated condensation product of naphthalene and formaldehyde,

an alkyl aryl sulfonic acid in which the alkyl group is C to C and the aryl group is benzene and naphthalene and its alkali metal salts, and

an alkyl phenol-ethylene oxide condensate having the formula IPQO H20 H20) ,11

where R is an alkyl group having from 6 to 12 carbon atoms and where n has a value of from 8 to 12-0.5 to parts, and an aluminum sequestrant selected from the group consisting of a polyhydroxy \carboxylic acid having the formula CH OH(CHOH),,COOH where n is 2 to 5, and its alkali metal salts,

a polyhydric alcohol of the formula CH OH (CHOH),,CH OH where n is 2 to 5, and

ethylenediamine tetraacetic acid and its alkali metal salts0.5 to 5 parts.

5. A composition for cleaning aluminum and its alloys in aqueous solution consisting essentially 'by weight of sodium tetra-borate35 to 92 parts, tetrasodium pyrophosphate-S to 35 parts, a water soluble hexavalent chromium compound selected from the group consisting of chromic acid, alkali metal chromates and alkali metal dichromates-O.3 to 4 parts, together with 0.5 to 5 parts each of the organic detergents selected from the group consisting of a sodium salt of a sulfonated condensation product of naphthalene and formaldehyde,

an alkyl aryl sulfonicacid in which the alkyl group is C to C and the aryl group is benzene and naphthalene, and its alkali metal salts, and

an alkyl phenol-ethylene oxide condensate having the formula 11-Qo 0 H20 H20) 11 where R is an alkyl group having from 6 to 12 carbon atoms and where n has a value of from 8 to 12, and 0.5 to 5 parts of an aluminum sequestrant selected from the group consisting of a polyhydroxy carboxylic acid having the formula "CH OH(CHOH) COOH where n is 2 to 5, and its alkali metal salts, a polyhydric alcohol of the formula CH OH(CHOH),,CH OH where n is 2 to 5, and ethylenediamine tetraacetic acid and its alkali metal salts. 6. A composition for cleaning aluminum and its alloys in aqueous solution consisting essentially by weight of 7 Parts sodium tetraborate tetrasodium pyrophosphate 17 potassium dichromate 5 sodium gluconate 1 a sodium salt of a sulfonated condensation product of naphthalene and formaldehyde 2 dodecylbenzenesulfonicacid 2 an alkyl phenol-ethylene oxide condensate having the formula where R is an alkyl group having from 6 to 12' carbon atoms and where n has a value of from 8 to 12 3 References Cited by the Examiner JULIUS GREENWALD, Primary Examiner.

J. T. FEDIGAN, Assistant Examiner. 

1. A COMPOSITION FOR CLEANING ALUMINUM AND ITS ALLOYS IN AQUEOUS SOLUTION CONSISTING ESSENTIALLY BY WEIGHT OF AN ALKALI METAL TETRABORATE-35 TO 92 PARTS, AN ALKALI METAL POLYPHOSPHATE-5 TO 35 PARTS, A WATER SOLUBLE HEXAVALENT CHROMIUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF CHROMIC ACID, ALKALI METAL CHROMATES AND ALKALI METAL DICHROMATES -0.3 TO 4 PARTS, AND AT LEAST ONE ORGANIC DETERGENT SELECTED FROM THE GROUP CONSISTING OF A SODIUM SALT OF A SULFONATED CONDENSATION PRODUCT OF NAPHTHALENE AND FORMALDEHYDE, AN ALKYL ARYL SULFONIC ACID AND ITS ALKALI METAL SALTS IN WHICH THE ALKYL GROUP IS C8 TO C14, THE ARYL GROUP IS BENZENE AND NAPHTALENE, AND AN ALKYL PHENOL-ETHYLENE OXIDE CONDENSATE HAVING THE FORMULA 